The invention is based upon a method as generally described by the preamble to the main claim and upon an information carrier in the form of a card produced according to this method and as generally described hereinafter. An identification card and a method for producing it are known from French Pat. No. 2,435,357, in which a light-sensitive layer or photo layer is applied to a carrier layer of polyvinylchloride (PVC). This photo layer itself is in turn made up of a sequential layering of a first polyester layer, a removable layer adjacent thereto, the actual light-sensitive layer, which has a thickness merely of a few .mu. and therefore corresponds to the photoemulsion, an adhesive layer adjacent thereto, and a lower protective layer, for instance, paper which has been treated in a specific manner. In this known method, it is of substantial significance that the emulsion layer is not exposed to light and its sensitivity is adjusted such that exposure to light is effected only with a particularly strong and intense light source, while normal ambient light is of little influence.
In producing this card, the procedure then is such that first the lower protective layer is removed, and the remaining coating having the film emulsion is pressed onto the PVC carrier layer, to which it adheres because of the adhesive layer already mentioned. The first polyester layer is then removed, which is facilitated by the removable intermediate layer located between the actual emulsion and this first polyester layer, and the card thus far prepared and having the film emulsion, which has not yet been exposed but is now uncovered, then travels from a magazine to an exposure station where exposure is performed under the influence of strong ultraviolet radiation. A number of developing, brushing, rinsing and drying steps then follow, during which a given card is transported, with the aid of reversable slides, into the individual baths and treatment stations. At a final station, a polyester protective layer is then applied by heat-pressing to the emulsion layer, which was until then still uncovered, although already developed. Nevertheless, it is not possible to preclude difficulties with an information card of this kind, which may arise either at that time or upon later use and are caused by insufficiently firm bonding of the polyester layer last applied with the remaining material making up the card, because as is well known, polyester cannot be made to adhere with sufficient fastness when it is heat-pressed.
A further problem is presented by the preparation of the card, in the course of which first two layers have to be removed from the photo layer encompassing the emulsion layer, and then this layer has to be glued in an intermediate step to the PVC carrier layer, all this being done while the emulsion is still unexposed and thus vulnerable. Furthermore, it cannot be precluded that the total effort of exposing and developing the emulsion which must be undergone during the process of producing the card may be in vain (since the identification card is not complete and the emulsion layer is not covered until the final polyester layer has been applied) because of damage to the just-exposed emulsion layer or the possible separation of this layer either partially or in its entirety in the various baths and brushing and drying stations. The total effort involved in producing an identification card of this kind is considerable. It may also be presumed with this known identification card that a colored version of the image cannot be obtained by ultraviolet exposure, because the development of a color photograph necessitates a substantially greater number of baths and intermediate steps than can be withstood, in terms of the stability and adhesion of the emulsion, given a method of this kind which involves belated exposure and development. Furthermore, it is not possible to obtain a color composition of the image that is pleasing to the normal eye by using an exclusively ultraviolet exposure method.
In summary, this known identification card is produced in the following manner. The starting material is an unfinished card, which on the obverse and reverse already has impressions (that is, data and writing) on its PVC card carrier. The reverse already has a plastic coating, specifically a plastic lamination, and on the obverse there is an area on which there is no information, to which the photo emulsion is then glued in the manner described above. After exposure to light and development, the obverse is then laminated as well by heat-pressing the polyester protective layer onto it. The manner in which the photo emulsion is glued to the PVC carrier is not described in this French patent; apparently the removal of the upper and lower protective or carrier layers, which together with the photo emulsion and further adhesive layers make up the light-sensitive coating, is a manual procedure. A further disadvantage of this known method of production is, finally, the fact that the belated exposure of the photo emulsion, in other words after the photo emulsion has been glued onto the PVC carrier, can be accomplished only poorly and with a sacrifice of quality, if for no other reason then because under practical conditions it is impossible to apply the adhesive layer, which is always required, so absolutely uniformly that distortions in making the image can reliably be avoided.
It is furthermore generally known, in producing an identification card carrying a photographic image of the user or bearer, to stamp an intermediate foil or coating to cut out a space of the same size and shape as the photograph to be inserted there, and then to place a finished photograph in the stamped-out area. Then further coatings and foils are disposed on either side of the card, and these plastic layers are sandwiched together via adhesives and/or the effects of pressure and heat. In so doing, an additional adhesive has to be applied at least where the photograph (which itself is a sandwich comprising the carrier and the emulsion) is located for the sake of the plastic layer which is to cover it, so that sufficient adhesion is assured at this location; otherwise, merely bending the identification card once or twice might cause separations and bubbles just at the place where the photograph of the bearer and/or other data are located.
With all types of passes or identification cards including or receiving an image or in any event a photographic layer, it is accordingly problematical that such images can be obtained only on a base of a type of material which cannot be bonded to the material making up these passes. Normally conventional photographs on paper are used, for instance Polaroid photographs, and no actual contact exists between the surface of the photograph and the plastic layers covering it. Even if an adhesive is applied, then it is only the photographic emulsion of the paper image which adheres to the adhesive, and if the identification card were arbitrarily opened--which is not precluded if there is an intent to counterfeit--the photographic emulsion would tear away. This accessibility involves security aspects which cannot be left unaddressed. Furthermore, the known provisions generally result in sacrifices in terms of the quality of such identification cards, because these cards are made of various materials. A prime example of the production of identification cards of this kind is offered by U.S. Pat. No. 4,101,701, for example, in which suitable glues and adhesives are also disclosed, so as to be able to effect the combination of the individual plastic layers with the Polaroid photograph placed among them.
Because of the known prior art, the problem accordingly exists of how an image--for instance, the representation of the bearer's face--can be attained in an identification card without this image acting as a foreign body in the card, without providing opportunities for counterfeiting and preferably without having the image in the identification card completely cover the area which it occupies, that is, without the image covering the area such that light cannot reach it.
As a matter of fact, because the image in the pass does have the character of a foreign body, as is also perceptible tactilely from the thickening at that location on the pass, there is the further danger that at such locations the pass or identification card will break--that is, in the vicinity of the edges; the danger of counterfeiting in a card of that kind also exists, because the inserted photograph can simply be cut out and replaced with another.
Identification cards may be embodied as personal passes, for instance enabling a particular person to attain access to an area not open to the public, or else they may be embodied as impersonal passes, for instance authorizing the bearer at a given time to obtain goods or services. The card and the means used to identify the bearer may be quite various, and they generally depend on the intended use for the card. Transferrable customer cards of department stores or credit organizations are made simply of a single plastic layer, on which the name of the issuer is printed and on which both the name and an individual identification number are stamped. In contrast, personal passes comprise a plastic laminate having a layer on which data visible to the human eye are entered in uncoded form, and which may also have a window for the emplacement of a photograph, as already mentioned. It is also possible for machine-readable data to be provided which are invisible to the human eye, or in any event are encoded such as not be comprehensible visually, perhaps disposed on a further layer, the data being readable by infrared radiation, for instance.
It is clear that producing an identification card is all the more difficult, the more data are disposed on the card. This is particularly true for the layer carrying the data which are visible to the human eye and entered in uncoded form, which generally encompass the name of the issuer, the designation of the area in which the card is valid, one or more identification numbers, the name and perhaps the address of the bearer as well as a photograph of the bearer. Only generalized information which is the same for many cards--for instance, the name of the issuer or the area of validity--can usually be placed on the card by machine, while the data pertaining to the bearer require a number of different manual operations which must be performed separately.
It is accordingly the primary object of the present invention to provide a method of producing identification cards which in comparison with known methods has been substantially simplified, which assures high quality of the final product (preferably including a color image), and which provides that the final product, namely the identification card, is also sufficiently counterfeit-proof.